1. Field of the Invention
This invention relates to a monitoring apparatus, a receiver, a sender and monitoring/notifying method for e-mail transmission system of receiver terminal.
2. Description of Related Art
In the recent years, internet facsimile terminal apparatuses for e-mail (IFAX) that receive/transmit data by using e-mail on the internet have become available, and they are disclosed in publications such as Japanese Laid Open Patent Application H08-242326 and its corresponding U.S. patent application Ser. No. 5,881,233.
Such IFAXes are different from normal facsimile machines that use telephone lines and do not negotiate with receiver terminals; therefore, they cannot confirm whether image information is actually delivered to receiver terminals. Conventionally, as a solution to the problem, delivery confirmation mail messages that notify reception status to sender IFAX from the receiver terminal have been proposed (RFC2532).
The conventional art has made it possible to confirm reception status from delivery confirmation mail messages, however, such delivery confirmation mail messages are made and transmitted by a receiver terminal, thus cannot be received when the power is off at the receiver terminal. The same is true when the receiver terminal is frozen for some reason.
When such a delivery confirmation mail message is not received, the sender IFAX must determine that the transmission has failed, only after a delivery time-out by the mail server. Also, when the receiver terminal is turned off, it is very likely that transmitted e-mail messages will not be read immediately, therefore, the sender may choose other means of communication (e.g., G3FAX) to transmit the message. However, e-mail apparatuses including recent IFAXes do not have the capacity to detect the condition (status) whether the power is turned off at receiver terminals, before transmitting messages.